1. Field of the Invention
The present invention relates to a disc apparatus of the automatic changer type for recording or reproducing an information signal on a desired disc taken out of a magazine containing a plurality of discs. More particularly, the present invention relates to a disc apparatus having a plurality of pickup units for recording or reproducing discs to significantly shorten the time (access time) between taking out a disc from the magazine and starting recording or reproducing the disc, and to stabilize such operations.
2. Description of the Related Art
Conventionally, a disc apparatus as mentioned above is known as disclosed in Japanese Non-examined Patent Publication No. Hei 5-89586. This disclosed disc apparatus has a magazine containing a plurality of discs and first and second changer devices for taking desired discs out of the tray for playback. If a subsequent disc to be reproduced is scheduled for playback before the end of playback by the first changer device, the second changer device moves in to reproduce the next selected disc.
Recently, along with the development of multimedia technologies, the video on demand (VOD) system has come to where desired music on CDs (Compact Discs) and movies can be enjoyed at home. A problem to overcome to fully implement and popularize the VOD and CATV (cable television) is to increase the speed of processing a huge amount of data to be supplied to users.
Consequently, for a disc apparatus suitable for implementing such a VOD system, namely a disc apparatus of the automatic changer type in which a plurality of discs such as music CDs, video CDs, and DVD programs are sequentially or simultaneously reproduced by a plurality of pickup units, it is necessary to shorten the disc handling time from loading discs to reproducing them as much as possible.
However, in the conventional apparatus as disclosed in the above-mentioned Japanese un-examined Patent Publication No. Hei 5-89586, the magazine is provided at both sides thereof with dedicated positions at which disc playback is performed by the first and second changer devices. Therefore, for example, if a subsequent playback disc is schedule for playback before the end of the playback being made by the first changer device, the second changer device to perform the next disc receives the same and must move to the dedicated position at which the disc is to be performed by the second changer device. This takes time before starting the playback of the next disc, still presenting a problem that the requirement for the processing speed required for implementing the VOD and CATV systems is not fully satisfied.
In addition, even if the speed requirement is satisfied by some means, achieving the stability of disc handling operations of the apparatus is another problem.
It is therefore an object of the present invention to provide a disc apparatus for selecting desired discs from a magazine, receiving a command for recording or reproducing the selected discs sequentially or simultaneously, and performing as instructed the recording or reproducing of the discs with a relatively short delay time.
It is another object of the present invention to provide a disc apparatus for stably performing the sequential or simultaneous recording or reproducing of selected discs.